Telecommunications apparatuses and methods

ABSTRACT

A method of allocating resources in a mobile telecommunications system, the resources being for a relay node to operate as a terminal-to-terminal relay for a device-to-device communication between a first terminal and a second terminal. The method includes: allocating first resources for the first terminal to communicate via the relay node for the device-to-device communication; allocating second resources for the second terminal to communicate via the relay node for the device-to-device communication; notifying the first terminal of the allocated first resources; notifying the second terminal of the allocated second resources; and the first and second terminals exchanging messages for the device-to-device communication via the relay node and using the first and second resources, respectively.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of U.S. application Ser. No.15/752,914, filed Feb. 15, 2018, which is based on PCT filingPCT/EP2016/073313, filed Sep. 29, 2016, which claims priority to EP15188113.3, filed Oct. 2, 2015, the entire contents of each areincorporated herein by reference.

FIELD

The present disclosure relates to telecommunications apparatuses andmethods.

BACKGROUND

The “background” description provided herein is for the purpose ofgenerally presenting the context of the disclosure. Work of thepresently named inventors, to the extent it is described in thisbackground section, as well as aspects of the description which may nototherwise qualify as prior art at the time of filing, are neitherexpressly or impliedly admitted as prior art against the presentinvention.

Mobile telecommunication systems, such as those based on the 3GPPdefined UMTS and Long Term Evolution (LTE) and Long Term EvolutionAdvanced (LTE-A) architecture, are able to support more sophisticatedservices than simple voice and messaging services offered by previousgenerations of mobile telecommunication systems. For example, with theimproved radio interface and enhanced data rates provided by LTEsystems, a user is able to enjoy high data rate applications such asvideo streaming and video conferencing on mobile communications devicesthat would previously only have been available via a fixed line dataconnection.

The demand to deploy fourth generation networks is therefore strong andthe coverage area of these networks, i.e. geographic locations whereaccess to the networks is possible, is expected to increase rapidly.However, although the coverage and capacity of fourth generationnetworks is expected to significantly exceed those of previousgenerations of communications networks, there are still limitations onnetwork capacity and the geographical areas that can be served by suchnetworks. These limitations may, for example, be particularly relevantin situations in which there is a desire for a group of terminal devices(communications devices) to exchange information with each other in afast and reliable manner. In order to help address these limitationsthere have been proposed approaches in which terminal devices within awireless telecommunications system may be configured to communicate datadirectly with one another without some or all their communicationspassing through an infrastructure equipment element, such as a basestation. Such communications are commonly referred to generally as adevice-to-device (D2D) communications. Many device-to-devicecommunications may be transmitted by one device to a plurality of otherdevices in a broadcast like manner and so in that sense the phrase“device-to-device communications” also covers “device-to-devicescommunications”.

Thus, D2D communications allow communications devices that are insufficiently close proximity to directly communicate with each other,both when within the coverage area of a network and when outside anetwork's coverage area (e.g. due to geographic restrictions on anetwork's extent or because the network has failed or is in effectunavailable to a terminal device because the network is overloaded). D2Dcommunications can allow user data to be more efficiently and quicklycommunicated between communications devices by obviating the need foruser data to be relayed by a network entity such as a base station. D2Dcommunications also allow communications devices to communicate with oneanother even when one or both devices may not be within the reliablecoverage area of a network. The ability for communications devices tooperate both inside and outside of coverage areas makes wirelesstelecommunications systems that incorporate D2D capabilities well suitedto applications such as public protection/safety and disaster relief(PPDR), for example. PPDR related communications may benefit from a highdegree of robustness whereby devices can continue to communicate withone another in congested networks and when outside a coverage area. 3GPPhas developed some proposals for such public safety D2D use in LTEnetworks in Release12.

In parallel, the development of relay nodes in telecommunications systemis expected to facilitate communications with the base stations andpotentially to expand the range of coverage of the base stations byrelaying communications between terminal devices and base stations.However, due to the complexity of D2D arrangements and in particular tothe lack of centralised control points (like the base stations in aconventional mobile network), there is at present a lack of relayingsolutions for D2D communications.

SUMMARY

According to a first example aspect, there is provided a method ofallocating resources in a mobile telecommunications system, theresources being for a relay node to operate as a terminal-to-terminalrelay for a device-to-device communication between a first terminal anda second terminal, the method comprising: allocating first resources forthe first terminal to communicate via the relay node for thedevice-to-device communication; allocating second resources for thesecond terminal to communicate via the relay node for thedevice-to-device communication; notifying the first terminal of theallocated first resources; notifying the second terminal of theallocated second resources; and the first and second terminalsexchanging messages for the device-to-device communication via the relaynode and using the first and second resources, respectively.

According to a second example aspect, there is provided a method ofoperating a terminal in a mobile telecommunications system and for usinga relay node as a terminal-to-terminal relay for a device-to-devicecommunication between the terminal and a further terminal, the methodcomprising the terminal: receiving one or more grant messages notifyingthe terminal of allocated resources for the relay node to relay thedevice-to-device communication; and the terminal exchanging messageswith the further terminal for the device-to-device communication, viathe relay node and using the allocated resources.

According to a third example aspect, there is provided a terminal foruse in a mobile telecommunications system and for using a relay node asa terminal-to-terminal relay for a device-to-device communicationbetween the terminal and a further terminal, the terminal comprising atransceiver and a controller, wherein the controller is configured to:receive, via the transceiver, one or more grant messages notifying theterminal of allocated resources for the relay node to relay thedevice-to-device communication; and exchange, via the transceiver,messages with the further terminal for the device-to-devicecommunication, via the relay node and using the allocated resources.

According to a fourth example aspect, there is provided circuitry for aterminal for use in a mobile telecommunications system and for using arelay node as a terminal-to-terminal relay for a device-to-devicecommunication between the terminal and a further terminal, wherein thecircuitry comprises a controller element and a transceiver elementconfigured to operate together to: receive one or more grant messagesnotifying the terminal of allocated resources for the relay node torelay the device-to-device communication; and exchange messages with thefurther terminal for the device-to-device communication, via the relaynode and using the allocated resources.

According to a fifth example aspect, there is provided a method ofallocating resources in a mobile telecommunications system, theresources being for a relay node to operate as a terminal-to-terminalrelay for a device-to-device communication between a first terminal anda second terminal, the method comprising: the relay node identifying aresource pool for terminal-to-terminal relaying; the relay nodeallocating first resources from the resource pool for the first terminalto communicate via the relay node for the device-to-devicecommunication; the relay node allocating second resources from theresource pool for the second terminal to communicate via the relay nodefor the device-to-device communication; the relay node transmitting oneor more grant messages notifying the first and second terminals of theallocated first and second resources; and the first and second terminalsexchanging messages for the device-to-device communication via the relaynode and using the first and second resources, respectively.

According to a sixth example aspect, there is provided a method ofoperating a relay node for allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising the relay node: identifying a resource pool forterminal-to-terminal relaying; allocating first resources from theresource pool for the first terminal to communicate via the relay nodefor the device-to-device communication; allocating second resources fromthe resource pool for the second terminal to communicate via the relaynode for the device-to-device communication; and transmitting one ormore grant messages notifying the first and second terminals of theallocated first and second resources.

According to a seventh example aspect, there is provided a relay nodefor allocating resources in a mobile telecommunications system, theresources being for a relay node to operate as a terminal-to-terminalrelay for a device-to-device communication between a first terminal anda second terminal, the relay node comprising a transceiver and acontroller, the controller being configured to: identify a resource poolfor terminal-to-terminal relaying; allocate first resources from theresource pool for the first terminal to communicate via the relay nodefor the device-to-device communication; allocate second resources fromthe resource pool for the second terminal to communicate via the relaynode for the device-to-device communication; and transmit, via thetransceiver, one or more grant messages notifying the first and secondterminals of the allocated first and second resources.

According to a eighth example aspect, there is provided circuitry for arelay node for allocating resources in a mobile telecommunicationssystem, the resources being for a relay node to operate as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, wherein the circuitry comprisesa controller element and a transceiver element configured to operatetogether to: identify a resource pool for terminal-to-terminal relaying;allocate first resources from the resource pool for the first terminalto communicate via the relay node for the device-to-devicecommunication; allocate second resources from the resource pool for thesecond terminal to communicate via the relay node for thedevice-to-device communication; and transmit one or more grant messagesnotifying the first and second terminals of the allocated first andsecond resources.

According to a ninth example aspect, there is provided a method ofoperating a base station in a mobile telecommunications system and forusing a relay node as a terminal-to-terminal relay for adevice-to-device communication between a first terminal and a secondterminal, the method comprising the base station: receiving, from therelay node, a resource pool allocation request; identifying a resourcepool for the relay node to allocate resources for terminal-to-terminalrelaying; notifying the relay node that the identified resource pool hasbeen allocated to the relay node to allocate resources forterminal-to-terminal relaying.

According to a tenth example aspect, there is provided a base stationfor use in a mobile telecommunications system and for using a relay nodeas a terminal-to-terminal relay for a device-to-device communicationbetween a first terminal and a second terminal, the base stationcomprising a transceiver and a controller, the controller beingconfigured to: receive, from the relay node and via the transceiver, aresource pool allocation request; identify a resource pool for the relaynode to allocate resources for terminal-to-terminal relaying; notify,via the transceiver, the relay node that the identified resource poolhas been allocated to the relay node to allocate resources forterminal-to-terminal relaying.

-   -   According to a eleventh example aspect, there is provided        circuitry for a base station for use in a mobile        telecommunications system and for using a relay node as a        terminal-to-terminal relay for a device-to-device communication        between a first terminal and a second terminal, wherein the        circuitry comprises a controller element and a transceiver        element configured to operate together to: receive, from the        relay node, a resource pool allocation request; identify a        resource pool for the relay node to allocate resources for        terminal-to-terminal relaying; notify the relay node that the        identified resource pool has been allocated to the relay node to        allocate resources for terminal-to-terminal relaying.

According to a twelfth example aspect, there is provided a method ofallocating resources in a mobile telecommunications system, theresources being for a relay node to operate as a terminal-to-terminalrelay for a device-to-device communication between a first terminal anda second terminal, the method comprising: the relay node requesting, toa base station, resources for relaying the device-to-devicecommunication; the base station allocating first resources for the firstterminal to communicate via the relay node for the device-to-devicecommunication; the base station allocating second resources for thesecond terminal to communicate via the relay node for thedevice-to-device communication; the base station notifying the relaynode of the allocated first and second resources; notifying the firstterminal of the allocated first resources; notifying the second terminalof the allocated second resources; and the first and second terminalsexchanging messages for the device-to-device communication via the relaynode and using the allocated first and second resources, respectively.

According to a thirteenth example aspect, there is provided a method ofoperating a relay node for allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising the relay node: requesting, to a base station, resources forrelaying the device-to-device communication; and receiving, from thebase station, a notification of allocated first resources and allocatedsecond resources, the allocated first resources being allocated for thefirst terminal to communicate via the relay node for thedevice-to-device communication and the allocated second resources beingallocated for the second terminal to communicate via the relay node forthe device-to-device communication.

According to a fourteenth example aspect, there is provided a relay nodefor allocating resources in a mobile telecommunications system, theresources being for a relay node to operate as a terminal-to-terminalrelay for a device-to-device communication between a first terminal anda second terminal, the relay node comprising a transceiver and acontroller, the controller being configured to: request, to a basestation and via the transceiver, resources for relaying thedevice-to-device communication; and receive, via the transceiver andfrom the base station, a notification of allocated first resources andallocated second resources, the allocated first resources beingallocated for the first terminal to communicate via the relay node forthe device-to-device communication and the allocated second resourcesbeing allocated for the second terminal to communicate via the relaynode for the device-to-device communication.

According to a fifteenth example aspect, there is provided circuitry fora relay node for allocating resources in a mobile telecommunicationssystem, the resources being for a relay node to operate as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, wherein the circuitry comprisesa controller element and a transceiver element configured to operatetogether to: request, to a base station, resources for relaying thedevice-to-device communication; and receive, from the base station, anotification of allocated first resources and allocated secondresources, the allocated first resources being allocated for the firstterminal to communicate via the relay node for the device-to-devicecommunication and the allocated second resources being allocated for thesecond terminal to communicate via the relay node for thedevice-to-device communication.

According to a sixteenth example aspect, there is provided a method ofoperating a base station in a mobile telecommunications system and forusing a relay node as a terminal-to-terminal relay for adevice-to-device communication between a first terminal and a secondterminal, the method comprising the base station: receiving, from arelay node, a request for resources for relaying the device-to-devicecommunication; allocating first resources for the first terminal tocommunicate via the relay node for the device-to-device communication;allocating second resources for the second terminal to communicate viathe relay node for the device-to-device communication; and notifying therelay node of the allocated first and second resources.

According to a seventeenth example aspect, there is provided a basestation for use in a mobile telecommunications system and for using arelay node as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the basestation comprising a transceiver and a controller, the controller beingconfigured to: receive, from a relay node and via the transceiver, arequest for resources for relaying the device-to-device communication;allocate first resources for the first terminal to communicate via therelay node for the device-to-device communication; allocate secondresources for the second terminal to communicate via the relay node forthe device-to-device communication; and notify, via the transceiver, therelay node of the allocated first and second resources.

According to a eighteenth example aspect, there is provided circuitryfor a base station for use in a mobile telecommunications system and forusing a relay node as a terminal-to-terminal relay for adevice-to-device communication between a first terminal and a secondterminal, wherein the circuitry comprises a controller element and atransceiver element configured to operate together to: receive, from arelay node requesting a request for resources for relaying thedevice-to-device communication; allocate first resources for the firstterminal to communicate via the relay node for the device-to-devicecommunication; allocate second resources for the second terminal tocommunicate via the relay node for the device-to-device communication;and notify the relay node of the allocated first and second resources.

According to a nineteenth example aspect, there is provided computersoftware which, when executed by a computer, causes the computer toperform any of the methods discussed above and according to a twentiethexample aspect, a storage medium which stores the computer software.

Further respective aspects and features are defined by the appendedclaims.

The foregoing paragraphs have been provided by way of generalintroduction, and are not intended to limit the scope of the followingclaims. The described embodiments, together with further advantages,will be best understood by reference to the following detaileddescription taken in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

A more complete appreciation of the disclosure and many of the attendantadvantages thereof will be readily obtained as the same becomes betterunderstood by reference to the following detailed description whenconsidered in connection with the accompanying drawings wherein likereference numerals designate identical or corresponding parts throughoutthe several views, and wherein:

FIG. 1 provides a schematic diagram illustrating an example of a mobiletelecommunication system;

FIGS. 2-5 schematically represent examples of terminal-to-terminal relayassistance;

FIG. 6 illustrates an example of a call flow for a D2D relayingresources allocation;

FIG. 7 illustrates another example of a call flow for a D2D relayingresources allocation;

FIG. 8 illustrates a further example of a call flow for a D2D relayingresources allocation;

FIG. 9 illustrates yet another example of a call flow for a D2D relayingresources allocation;

FIG. 10 illustrates an example method of allocating D2D relayingresources;

FIG. 11 illustrates another example method of allocating D2D relayingresources;

FIG. 12 illustrates a further example method of allocating D2D relayingresources; and

FIG. 13 illustrates an example terminal and an example base station in atelecommunications system.

DETAILED DESCRIPTION OF THE EMBODIMENTS

FIG. 1 provides a schematic diagram illustrating some basicfunctionality of a mobile (cellular) telecommunications network/system,in this example operating generally in accordance with LTE principles,and which may be adapted to implement embodiments of the disclosure asdescribed further below. Various elements of FIG. 1 and their respectivemodes of operation are well-known and defined in the relevant standardsadministered by the 3GPP (RTM) body, and also described in many books onthe subject, for example, Holma, H. and Toskala, A. [1]. It will beappreciated that operational aspects of the telecommunications networkwhich are not specifically described below may be implemented inaccordance with any known techniques, for example according to therelevant standards and known variations thereof. Furthermore, it will beappreciated that whilst some specific examples described herein mayrefer to implementations based around particular 3GPP implementations,the same principles can be applied regardless of the underlyingoperating principles of the network. That is to say, the same principlescan be applied for wireless telecommunications networks operating inaccordance with other standards, whether past, current or yet to bespecified.

The network includes a plurality of base stations 101 connected to acore network 102. Each base station provides a coverage area 103 (i.e. acell) within which data can be communicated to and from terminal devices104. Data is transmitted from base stations 101 to terminal devices 104within their respective coverage areas 103 via a radio downlink. Data istransmitted from terminal devices 104 to the base stations 101 via aradio uplink. The uplink and downlink communications are made usingradio resources that may be used by the operator of the network 100. Thecore network 102 routes data to and from the terminal devices 104 viathe respective base stations 101 and provides functions such asauthentication, mobility management, charging and so on. In addition tothe base stations 101 and terminal devices 104, the system may furthercomprise one or more relay nodes/devices 105. These may be used toenhance coverage for terminal devices operating in the relevant cell(s).The deployment of relay nodes (e.g. in terms of their locations) mayfollow generally established techniques for using relay nodes to supportcoverage in wireless telecommunications systems by assisting downlinkand/or uplink communications. In terms of terminology, it will beappreciated that terminal devices may also be referred to as mobilestations, user equipment (UE), user terminal, mobile radio, mobileterminal, mobile device and so forth. Similarly, base stations may alsobe referred to as transceiver stations/nodeBs/e-nodeBs, and so forth.Furthermore, relay nodes may also be referred to as relaydevices/relays, and so forth. In some example implementations of thepresent disclosure, a terminal device may be operating as a relay nodeto assist in supporting communications associated with other terminaldevices. That is to say, the functionality of a relay device may beprovided by a suitably configured terminal device.

Mobile telecommunications systems such as those arranged in accordancewith the 3GPP defined Long Term Evolution (LTE) architecture use anorthogonal frequency division multiplex (OFDM) based interface for theradio downlink (so-called OFDMA) and the radio uplink (so-calledSC-FDMA).

FIGS. 2-5 schematically represent examples of terminal-to-terminal relayassistance. In the example of FIG. 2, the mobile node operating as arelay (that will sometimes be referred to as Relay Node or “RN”) and thetwo terminals UE1 and UE2 are all within coverage of the base station(eNB), with the terminals being located at the edge of the cell. In aconventional arrangement, if UE1 and UE2 are under coverage of a basestation and wish to set up a D2D communication, they have to requestresources from the base station and wait for the base station'sallocation before they can fully establish the D2D communication. If oneof UE1 or UE2 receives a grant, sometimes referred to as an uplinkgrant, from the base station that indicates the resources allocation,conventionally it will announce the allocated resources in a broadcastscheduling assignment. Once the other one of UE1 and UE2 gets thisresource allocation information, they can both start the D2Dcommunication on these specific resources. In cases where the linkbetween UE1 and/or UE2 and the base station is of poor quality (e.g.with a weak power and/or interferences from other signals), the uplinkgrant (for both the sending of the scheduling assignment and for the D2Dcommunication data) may not always be received from the base station andany future control signalling from the base station may also suffer fromthe same problem. In a case where another terminal, or any other type ofmobile mode or device, is located between the base station and the celledge terminals, this terminal could operate as a RN, as illustrated inFIG. 2, for assisting one of or both of the establishment of the D2Dlink and any subsequent D2D data communication. For example, if the RNmobile node is to operate as a terminal-to-terminal relay node, the basestation may sent a grant for resources for UE1-RN communications andanother one for UE2-RN operations and then the RN can assist with thesetting up and with the carrying out of the terminal-to-terminalcommunications between UE1 and UE2. Also, by using a relay between UE1and UE2, whether at the edge of the cell or not, the transmission powerused by these UEs can be reduced thereby assisting with reducing powerconsumption and interferences.

In another example, illustrated in FIGS. 3 and 4, the terminals UE1 andUE2 are out of coverage of the base station. In the example of FIG. 3,UE1 and UE2 are located outside the cell for the base station with theRN being located within the cell while UE1 and UE2 are located insidethe cell for the base station with the RN being located outside therange of the base station (such that the presence or absence of a basestation has no relevance). In a conventional D2D system, if UE1 and UE2decide to establish a D2D communication, one of the two terminals canselect resources from a resource pool to transmit messages comprisingcontrol and/or data information. The resource pool can bepre-configured, and/or semi-statically allocated. While some resourcecollision with other D2D communications in the proximity of the twoterminals may occur with this type of an autonomous selection scheme,this is outside the scope of the present disclosure. If another terminal(or another mobile node) is located within range of both theseterminals, the assistance of such a mobile node as aterminal-to-terminal relay node could help the D2D communicationsbetween the two terminals. Also, in some examples, such a RN could alsoact as a central controller for the allocation of D2D resource from aD2D resource pool. As a result, the quality of D2D communication linkbetween UE1 and UE2 can be improved using the relay node, andpotentially the quality of other D2D communications in the area can alsobe improved if the level of resources collision and/or interferences canbe reduced.

In yet another example illustrated in FIG. 4, the terminals UE1-UE3 andthe mobile node RN are located in the same area. None, some or all ofthese four mobile nodes may be within the range of a base station(whether on the edge of the cell or not) or may be out of coverage. UE2and UE3, which are relatively distant from each other may have somedifficulty establishing or maintaining a D2D link. One of the possibleoptions for improving the situation is to increase the transmissionpower of the terminals so that their respective transmissions can reachthe other terminal more easily. However, this option will increase thepower consumption of the UE and may also cause (or increase the effectof) interferences to other communications in the area. On the otherhand, if at least one mobile node is situated in-between UE2 and UE3(e.g. RN and UE1 in FIG. 5) and could assist these terminals with theirD2D communication, the effect of some of the above disadvantages can bereduced. For example, if at least one terminal (e.g. RN, UE1) situatedin between the two D2D terminals (e.g. UE2, UE3) could work as a relayfor these two D2D terminals or assign another terminal (e.g. UE1, RN) asthe terminal-to-terminal relay for these two D2D UEs, the D2Dcommunications could be improved. In one example, and referring back toFIG. 5, RN may be operating as a relay for D2D communications betweenUE2 and UE3, either by default or by selection, and this mobile node mayalso be configured to assign the relay function to UE1 so that UE1becomes the terminal-to-terminal relay for D2D communications betweenUE1 and UE2. Additionally, such a terminal may also assist in managingthe resource allocation for one or more D2D terminals in the area.Accordingly, using such a terminal-to-terminal relay may help inimproving the overall network performance while limiting the negativeeffect on the energy efficiency and spectrum efficiency of the network.

While terminal-to-terminal relaying can bring some benefits to a mobiletelecommunications system, it is presently unclear how the allocationsof resources for terminal-to-terminal or device-to-device relaying canbe carried out.

According to the present disclosure, there are provided methods andexamples of allocating resources for a relay node to operate as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal.

In one example, hereinafter referred to as the first example, theterminal-to-terminal or D2D relaying resources are allocated under anetwork control mode. In a case where at least the relay node is undercoverage of a base station, but also in cases where the D2D UEs arewithin the range of the base station as well, the D2D UEs will beallocated resources by the base station for communicating via the relaynode or relay UE for their D2D communication. For example, the D2D UEscan ask for resources to be allocated for discovery, data communicationand/or control-related information (e.g. for D2D UEs themselves as wellas for relay UE) to network, through the relay UE sidelink or to thebase station, each time the D2D UEs have identified the relay UE as theD2D relay for their D2D communication(s). For the relay to be selectedas a D2D relay, it is generally expected to have a relatively good linkquality with the network as well as the relevant D2D UEs, although thedetailed identification and selection of a D2D relay node is not thesubject of the present disclosure. The skilled person is directed to theEP application number 15188002.8 filed by the Applicant on 1 Oct. 2015,which is incorporated by reference herein in its entirety, for adiscussion of possible methods and arrangements for selecting a relaynode in a mobile telecommunications network. Once the relay UE receivesthe corresponding control signalling from network notifying it of theresources allocated for relaying the D2D communication and once the D2Dhave also been informed of at least the allocated resources that arerelevant to them (e.g. from the network or via the relay UE forwardingthis information to them on a sidelink control channel), the D2Drelaying may start. For example, the relay UE can then monitor theallocated resources for discovery, control and communication messagesfrom the neighbouring D2D UEs on corresponding channels, and forwarddiscovery and communication messages to the desired destination inaccordance with a D2D or terminal-to-terminal relaying arrangement.

FIG. 6 illustrates an example of a call flow for a D2D relayingresources allocation. In this example a relay node is selected to act asa relay for a D2D unicast communication from UE1 to UE2, based onmeasurements from UE1, UE2 and the relay UE. In a case where the UE1-UE2link is having a poor or low quality for example, the relay may then beidentified as a possible help for the D2D communication. The network canfor example configure UE1, UE2 and optionally neighbouring UEs (aspossible relay candidates) to carry out and report on measurements.Measurement reports can then be sent, for example once a measurementevent has been triggered by the measured link quality. In some cases,the neighbouring UEs may not necessarily be in a connected (e.g.RRC_CONNECTED) state, but for them to send the measurement report, theymay have to transition to a connected state, for example with thenetwork sending a RRC connection establishment signalling. They may thenbe able to send the measurement report, if appropriate, and may thenreturn to a non-connected (e.g. RRC_IDLE) state. Based on the receivedmeasurement reports, the network may then select a relay for them. Asthe relay will assist with a unicast D2D communication from UE1 to UE2,in this example, the relay can be identified as such in the relaynotification. It is noteworthy that the method(s) for selecting a relayand for notifying the relevant nodes of the selected relay may vary.

Once the UE1 has been notified of the selected relay (or has identifiedthe relay if it is identifying the relay itself), it can send a resourcerequest to the relay to request a resource allocation for datatransmission. The relay can then transmit the allocation request tonetwork (e.g. to the base station) for the resource allocation of theappropriate UE-Relay links. As in this example the relaying is for aunicast and unidirectional communication from UE1 from UE2, the basestation can allocate resources from UE1 to the relay and from the relayto UE2. The base station can then notify the relay and, once the relayhas received the resource allocation from the base station, the relaycan notify the relevant terminals, i.e. UE1 and UE2 in this example,e.g. through a sidelink control channel. It is noteworthy that in a casewhere the terminals are also within range of the base station, they canbe notified of the allocated resources by the base station directlyrather than from the relay node.

Now that the resources have been allocated and notified o all relevantparties, UE1 can start the unicast transmission to UE2, through relay UEusing the resources allocated to that end (UE1→relay resources). Therelay node can then forward the messages to UE2 using the resourcesallocated to that end (relay→UE2 resources). Although different relayingscheme may be applied, it is expected that during data transmission, theUE1 will set its ID as the source and UE2 ID as the destination andthat, once the relay node receives the messages with the UE1 as thesource and UE2 as the destination, rather discarding them (as they arenot destined to the relay) it may first check or determined whether themessage is to be relayed. As the relay is aware that it is operating asa D2D relay from UE1 to UE2, based on the source and destination IDs itcan identify that the messages related to a relayed communication and itcan then forward the message to UE2 (in some example, with themodification of the source to its own ID, if appropriate based on therelaying scheme implemented). In a case where the relay is responsiblefor notifying, via the sidelink, the terminals of the allocatedresources may use or reuse a sidelink control channel, such as a PC5control channel as presently used in a D2D environment, for exampleusing a scheduling assignment scheme that is already in place, therebyminimising the amount of changes to be made to the existingarrangements, if such changes are considered as preferably limited.

It is noteworthy that although this example uses the example of aunidirectional communication (UE1 to UE2), in some cases resources maystill be allocated in the UE2 to UE1 direction (e.g. if ACK and/or NACKmessages are expected from UE2 to UE1) and the same principles apply toa bidirectional communication between UE1 and UE2. Generally anypossible form of UE1 communicating with UE2 is being considered underthe present disclosure, e.g. for this example and the other examples,e.g. unicast, groupcast and broadcast communications, unidirectional orbidirectional communications, etc.

Returning to this first example, the network is in charge of allocationresources, for example via the base station, and the relay and the D2DUEs can then comply to the relaying arrangement selected (and notified)using the allocated resources. Such a centralised arrangement canfacilitate an optimised use of resources, with for example the basestation being capable of allocating resources for D2D relaying in onearea while allocating resources for D2D relaying in a neighbouring areawhich are less likely to cause interferences and/or allocating at leastsome of these resources for D2D relaying, or for another use, at anotherend of the cell e.g. when it is expected that the allocating of theseoverlapping resources will not cause a conflict or interferences.Accordingly the use of the resources within the cell can be potentiallyimproved by using the network or base station as the entity allocatingthe resources for the D2D relaying.

In another example, hereinafter referred to as the second example, theterminal-to-terminal or D2D relaying resources are allocated under ahybrid control mode wherein a first set of resources, or resource pool,is allocated by the network to a relay node and the relay can thendecide how to allocate the resources in the resource pool, forcommunications with terminals to carry out D2D relaying. In this otherexample, such a partial network control mode is being implemented. Aresource pool is configured by the network for UE-to-UE relay via therelay node where the resource pool could be semi-configured ordynamically configured by the network. For example, a semi-configuredresource pool can be signalled by higher layer to the relay and/or thecorresponding D2D UEs, such as by indicating an identifier for a poolidentifying the pool amongst the variety of pools that arepre-configured. In one example using a dynamic resource pool, the relayUE can ask the resource allocation for its local D2D sub-network to thenetwork each time a resource pool is needed (e.g. if no resource poolwas previously configured and the relay will now operate as a relay orif a resource pool was previously configured but the relay requiresadditional resources to perform the relaying). Once the resource poolhas been allocated to the relay, this relay can decide by itself how toallocate the resources of the resource pool to the D2D UEs it isinteracting with and can send them the corresponding controlinformation, e.g. on a sidelink. The relay UE can then monitor theallocated resources for communications from the neighbouring UEs,including for example their discovery, control and communicationmessages on corresponding channels, and forward the communications (e.g.discovery and communication messages) to the desired destination.Accordingly a local D2D link through the relay can be established. Inthis second example, the relay can operate as the central node forresource allocation, in a similar fashion to how a base station/aneNodeB operates, and send control signalling as well, while it stillremain under some network supervision.

FIG. 7 illustrates another example of a call flow for a D2D relayingresources allocation. In this example, it is assumed that UE1 has anexisting D2D unicast communication with UE2 but their link is currentlypoor quality. Accordingly, UE1 may send a relay request to network andthe network can select a relay for their communication. In some cases,for the terminal to send the relay request, terminal (UE1 in thisexample) may not have to be in a connected (e.g. RRC_CONNECTED) state.And in some cases, for the terminal to receive the relay notificationfrom the network by dedicated signalling, it may have to be in aconnected state and, in this case, it may have to be transitioned into aconnected (e.g. RRC_CONNECTED) state. An example procedure of theUE-to-UE unicast relay establishment is depicted in FIG. 7 although, asthe skilled person will understand, any other suitable arrangement ormethod for identifying/selecting the relay and notifying the relayselection may be implemented. As previously mentioned, in this secondexample, a semi-persistent resource pool or dynamic resource pool may beallocated to the relay for this relay node to schedule the resources forits UEs. In the example illustrated in FIG. 7, a dynamic resource poolcase is being shown but the same teachings and principles can be appliedequally to a semi-persistent resource pool case. In this example, onceUE1 receives a Relay Notification message indicating the identifier ofthe selected relay (the relay UE ID), it will send a resource request tothis relay to request an allocation of resources for data transmissionfor its unicast D2D communication with UE2. In the example illustratedin FIG. 7, this will trigger the relay request a resource poolallocation to the network. However, in other examples, the relay maysend the resource pool allocation request to the network of its ownvolition such that the messages regarding the allocation of the resourcepool to the relay may occur before the terminal request resources to therelay node. Once the relay has received a resource pool allocation, itcan autonomously decide on the specific resource allocation for UE1 andUE2 for their D2D communication and it can then send the relevantterminals an allocation notification message informing them of theallocation results, e.g. through sidelink control channel. On theallocated resources have been notified to the terminals, UE1 can startthe unicast data transmission to UE2, through the relay and using theallocated resources selected from the resource pool, and vice versa, asappropriate.

It is noteworthy that, as explained in respect of FIG. 6, the teachingspresented in respect of this example apply equally to any other suitableD2D communication to be assisted, e.g. a unicast, groupcast or broadcastcommunication and a unidirectional or bidirectional communication.

Also, if the relay node determines that the resource pool is no longerrequired and/or that a smaller resource pool may be sufficient, it cannotify the network that the resource pool is released or that a smallerresource pool may be allocated, respectively. In the latter case, thenetwork can respond with a new or updated resource pool allocation andthe same principles discussed above can apply with the relay nodeallocating resources (or re-allocating resources if appropriate) to D2Dterminals for assisting with their D2D communications using relaying.

Accordingly the relay node may semi-autonomously allocate the resourcesfor the relaying. While the relay will select which resources toallocate to assist an existing D2D communication, the resources areselected from a resource pool which—in this example—is allocated to therelay by the network. Accordingly, the network can have some oversightover which resources are used in which areas while it will not have touse its own wireless and/or computing resources to handle the actualallocation of resources for assisting D2D communications by relaying.Accordingly, the burden on the network can be reduced by having therelay node allocating the relaying resources.

In accordance with a third example of the present disclosure, there isprovided an arrangement where the relaying resources are allocatedwithout any specific network control. In this case, the relay node canoperate using a pre-configured resource pool. The pre-determinedresource pool configuration could be broadcast to the network orpre-configured in relay. As in the second example, the relay UE will beresponsible for allocating the resources to UEs when the UE-to-UErelaying is being configured.

FIG. 8 illustrates another example of a call flow for a D2D relayingresources allocation. Although the third example is also applicable tounicast communications, as the previous examples have been illustratedfor relaying unicast communications, this third example will beillustrated in the context of a broadcast and of a groupcastcommunication. As the skilled person will understand, the teachingsdiscussed in respect of broadcast and groupcast communications in thecontext of this third example are also applicable to the first andsecond examples presented above and the techniques discussed above inrespect of unicast communications are equally applicable to the presentexample. In this example UE1 is in D2D broadcast communication with itsneighbours. UE2, UE3, UE4 and UE5. However, the links between UE1 andits neighbours may be suffering from a low quality, for example becauseUE1 may not be located in an ideal “centre” of the broadcast group. Inthis example, a self-triggered relay UE nearby sends a relay nodeindication message to indicate its role as a relay once it hasidentified that it can assist with the communication. The rule used forthe self-trigger ay for example that it has a good or good-enoughaverage link quality with all the relevant UE1's neighbouring UEs. Itcan be decided that this terminal can assist by relaying messages forthe D2D communication and can thus work as an intermediate node to relaythe message from UE 1 to the others. Such a relay may sometimes bereferred to as a UE-to-UE or terminal-to-terminal “broadcast” relay.Again, it is noteworthy that the procedure to select the relay andnotify the relay selection shown in FIG. 8 is purely illustrative andthat other methods or techniques may be used in this third example.

In this third example, the relay already has is a pre-configuredresource pool for operating as a relay node and to schedule theresources for the UEs it is assisting. In this example the sender UE1sends a relay request and the relay UE then sends a relay notificationto UE1 as well as to all the other UEs. In this example, once UE1receives the Relay Notification that indicates the relay UE ID, it sendsa resource request to the relay to ask the resource allocation for itsdata transmission. The relay UE can then decide on the specificresources for UE1 to transmit the data from UE1 to relay itself, as wellas the specific resources for the other UEs to receive the data fromrelay (and originally from UE1). The relay then sends a notification forthe resource allocation results to UE1, and to all the other UEs for thebroadcast communication. Using the received allocated resourcesnotification, UE1 can start a unicast data transmission to the relay,which will in turn broadcast the corresponding received data to all theother UEs.

For the sake of completeness, an example with a relaying assistance withgroup cast communications is also hereby illustrated with respect toFIG. 9 and in the context of the third example (although it is alsoapplicable to the other examples). FIG. 9 illustrates a further exampleof a call flow for a D2D relaying resources allocation. In this example,as in the example of FIG. 8, UE1 is in D2D broadcast communication withUE2, UE3, UE4 and UE5. In this case, while UE2 and UE3 receive thesignals from UE1 with a relatively good quality, UE4 and UE5 have poorquality links with UE1—for example because they are relatively far fromUE1 or for any other reason. In this example, a self-triggered relay UEnearby sends a relay node indication message to indicate its role as arelay, where the relay UE has good link quality with UE1 as well as withUE4 and UE5. Then this relay UE can operate as an intermediate node torelay the message from UE 1 to UE4 and UE5, but as UE2 and UE3 haverelatively good quality links with UE1, the relay does not operate as arelay for these two terminals. Such a relay node can sometimes bereferred to as a UE-to-UE or terminal-to-terminal groupcast relay as itrelays messages for a group of one or more terminals where the messagesare broadcast messages to the group of terminals and additionalterminals such that the group is made of some but not all of theintended broadcast recipients for the D2D broadcast messages. As thisfigure also illustrates another situation with the third example, apre-configured resource pool is also used by the relay node to scheduleand allocate the resources for its UEs. In this example, it is assumedthat the sender UE1 is the first one to detect the bad quality linkswith UE4 and UE5, and, as a result, sends the relay request. In otherexamples, it could be UE4 and UE5 sending the relay request, or anyother relevant mobile node (e.g. terminal, relay node, base station,etc.). Once a relay has been selected and UE1 receives a RelayNotification indicating the relay UE ID for the selected relay, it cansend a resource request to relay to ask for resources to be allocatedfor its transmissions. Once this request has been received, the relaycan decide the specific resources for UE1 to transmit the data from UE1to relay, as well as the specific resources for UE4 and UE5 to receivethe data from relay which was originally sent by UE1. In some cases, theresource request may be sent by UE4 and/or UE5 instead of UE1. Also, ifthe mobile telecommunication does not provide the means to transmit arelayed message to UE4 and UE5 at the same time (e.g. using a multicastarrangement, creating a group for broadcasting the message to the groupcontaining UE4 and UE5), the relay may then have to allocate resourcesfor sending a first message to UE4 and separate resources for sendinganother message to UE5 when relaying a single original message from UE1to both UE4 and UE5. This may for example depending on the messageaddressing techniques used to address the different UEs and on whetherthese techniques enable the relay to relay one message from UE1 as asingle message or as multiple messages to multiple UEs. Once theresource(s) have been selected from the resource pool, the relay cansend a notification regarding the resource allocation results to UE1,UE4 and UE5. With the received resource allocation notification, UE1 cansend a unicast data transmission to relay (or the relay may receive thecommunication from the original broadcast message broadcasted to theremaining UEs) and the relay can transmit the corresponding data to UE4and UE5 by groupcast, using the allocated resources.

Accordingly, by having the resources entirely managed by the relay node,the burden on the network can be made smaller by reducing the amount ofcomputing resources and signalling to be exchanged by the base station.However, on the other hand, such an arrangement may result in a lessoptimal distribution of resources within the network as the overallallocation of resources is not as supervised by the network as in thesecond example, let alone the first example. Accordingly, depending onthe specific needs at a point in time, it may be decided that one of thefirst, second or third examples may be preferable in the situation athand.

Examples methods of allocating resources in a mobile telecommunicationsnetwork will now be discussed with respect to FIG. 10-12. FIG. 10illustrates an example method of allocating D2D relaying resources. Themethod 1000 starts and at S1001 first resources are allocated for thefirst terminal to communicate via the relay node for thedevice-to-device communication while at S1002 second resources areallocated for the second terminal to communicate via the relay node forthe device-to-device communication. Then at S1003 and S1004 the firstand second terminal, respectively, are notified of the allocated firstand second resources, respectively. Then at S1005 the first and secondterminals can exchange messages for the D2D communication via the relaynode and using the first and second resources, respectively.

FIG. 11 illustrates another example method of allocating D2D relayingresources. The method 1100 starts and at S1101 the relay node identifiesa resource pool for terminal-to-terminal relaying. In some example thismay involve identifying a pre-determined resource pool while in othercases this may involve identifying an already allocated resource pool orrequesting a resource pool allocation to the network. Then, at S1102 therelay node allocates first/second resources from the resource pool forthe first/second terminal—respectively—to communicate via the relay nodefor the D2D communication. For example, the resources can be for aunicast transmission to the terminal or can be for a broadcasttransmission that will reach this terminal. Then at S1103 the relay nodecan transmit one or more grant messages notifying the first and secondterminals of the allocated first and second resources. In one example itcan send one grant message (resource allocation notification) to eachterminal and in another example it can broadcast the resource allocationnotification to at least the first and second terminals. Then the firstand second terminals can exchange messages for the D2D communication viathe relay node and using the first and second resources, respectively.

FIG. 12 illustrates a further example method of allocating D2D relayingresources. The method 1200 starts and at S1201 with the relay noderequesting to a base station resources for relaying the device-to-devicecommunication. Accordingly, the base station allocates first/secondresources for the first/second terminal—respectively—to communicate viathe relay node for the D2D communication (S1202). Then at S1203: thebase station notifies the relay node of the allocated first and secondresources. At S1204, the first/second terminals are notified of theallocated first/second resources. In some example, the base station cannotify them of the allocated resources while in other example, the relaynode may notify them. As the relay is expected be within range of thetwo terminals in all cases (as it has been selected as a relay) whilethe base station may not always have the terminals within its range, itmay be decided that the relay node will always send this notificationwith a view to avoiding making the arrangement more complex. Then atS1205, the first and second terminals exchange messages for the D2Dcommunication via the relay node and using the first and secondresources, respectively.

FIG. 13 illustrates an example terminal (1310) and an example basestation (1320) configured to communicate with each other and which mayimplement one or more techniques as discussed herein. The terminal 1310comprises a receiver 1311 and a transmitter 1312 connected to an antennafor communicating via a wireless interface. The terminal also comprisesa controller 1313 for controlling at least the receiver and transmitterof the terminal 1310. In some example, the terminal may be configuredsuch that the controller, receiver and transmitter may be configured tooperate together to operate as a D2D relay node to assist communicationfrom other terminals. Likewise, the base station 1320 comprises areceiver 1321 and a transmitter 1322 connected to an antenna forcommunicating via a wireless interface. The base station 1320 alsocomprises a controller 1323 for controlling at least the receiver andtransmitter of the base station 1320. The base station and terminal cancommunicate over the air, via the wireless interface by transmittinguplink signals from the terminal to the base station and downlinksignals from the base station to the terminal. D2D Terminals can alsocommunicate with each other directly using sidelink signals. A relaynode in accordance with the present disclosure may also have the samestructure as the terminal and/or base station.

While FIG. 13 shows a schematic illustration of a terminal and of a basestation, it will be appreciated that while in examples of the presentdisclosure, each terminal includes a transmitter, receiver andcontroller and each base station includes a transmitter, receiver andcontroller so as to allow communication between the terminals and/orbase stations, the terminal and base station may be implemented usingany appropriate technique. For example, the controller may comprise oneor more processor units which are suitably configured/programmed toprovide the desired functionality described herein using conventionalprogramming/configuration techniques for equipment in wirelesstelecommunications systems. For each terminal, the transmitter, receiverand controller are schematically shown in FIG. 13 as separate elementsfor ease of representation. However, it will be appreciated that foreach terminal the functionality of these units can be provided invarious different ways, for example using a single suitably programmedgeneral purpose computer, or suitably configured application-specificintegrated circuit(s)/circuitry, or using a plurality of discretecircuitry/processing elements for providing different elements of thedesired functionality. It will be appreciated the terminals will ingeneral comprise various other elements associated with their operatingfunctionality in accordance with established wireless telecommunicationstechniques (e.g. a power source, possibly a user interface, and soforth).

It is noteworthy that the teachings of the present invention whenpresented in respect of a first terminal and a second terminal includecases where the communications are broadcasted and where the secondterminal is one of the recipient of the broadcasted messages. Also,generally in the examples, the arrangements discussed involve first arelay notification identifying the relay node and then resource requestfollowed by a resource allocation response, e.g. by the relay node.However, in other cases less signalling may be involved and the relaynotification may also include the notification of the resourceallocation. For example, once the relay has been selected, it can selectthe resources to be allocated to the first and second terminals and atthe same time as notifying the terminals of its relay role, it caninform/notify them of the resources that have been allocated for thisnode to relay the relevant messages from the assisted D2D communication.

Also, generally the allocation of resources has been discussed hereinbut the same principles apply to the release of resources. Generally anyelement that can allocate resources can also release them if deemedappropriate (e.g. following a determination) or may be informed that theresources are no longer needed and have been released or can bereleased. For example, in the second and third example, the relay nodecan release resources that have been allocated for assisting a D2Dcommunication, while in the second example it may also release orrequest the a release of the resource pool that had been allocated toit. In the first example, the base station/the network can release theresources allocated for the relay node to assist with the D2Dcommunication.

Therefore, in accordance with the present disclosure, there is providedan arrangement in which the D2D communications can be assisted usingterminal-to-terminal relaying between a first D2D terminal and one ormore other D2D terminals and where resources can be appropriatelyallocated for the terminal-to-terminal relaying. It is noteworthy thatwhile existing LTE Rel'12 and Rel'13 standard outlines some relayingsolutions, these have been designed to address public safetycommunications (ProSe) which are mainly UE-to-Network relay oriented,such that they can be unhelpful when considering the different situationof terminal-to-terminal relaying, in particular for both or eitherunicast or broadcast D2D communications.

It is also noteworthy that, in accordance with the present disclosureand as previously discussed, the allocation of resources for therelaying may be based on the type of D2D communication, for example oneof unicast, multicast or broadcast or, for current D2D standardsproposed by the 3GPP consortium, one of unicast or broadcast. In theseexamples, this could for example affect the amount of resources to beallocated, in particular if a broadcast communication leads to agroupcast relaying.

In the examples above where information has to be sent from a terminalto another mobile node (e.g. a relay node or a base station), theterminal may not always be already in a connected state and might haveto change to a connected mode to send the information, and the terminalmay then change back to a non-connected state. For example, in a casewhere a neighbouring terminal (regardless of it being a request terminalor not) wishes to send a measurement report to a base station, aterminal or a relay node, in a 3GPP environment using an RRC protocol,the neighbouring terminal may not be in a RRC_CONNECTED state. In thiscase, the terminal may transition to a RRC_CONNECTED state, for examplefollowing the network (e.g. the base station) sending RRC connectionestablishment signalling, so that the terminal can send the measurementreport. The terminal may then transition back to the RRC_IDLE state, ifappropriate.

Additionally, the method steps discussed herein may be carried out inany suitable order. For example, steps may be carried out in an orderwhich differs from an order used in the examples discussed above or froman indicative order used anywhere else for listing steps (e.g. in theclaims), whenever possible or appropriate. Thus, in some cases, somesteps may be carried out in a different order, or simultaneously or inthe same order. For example, in the method of FIG. 10, S1001-S1002 maybe carried out in any suitable order, such as one after the other(S1001-S1002 or S1002-S1001) or at least partially in parallel. So longas an order for carrying any of the steps of any method discussed hereinis technically feasible, it is explicitly encompassed within the presentdisclosure.

As used herein, transmitting information or a message to an element mayinvolve sending one or more messages to the element and may involvesending part of the information separately from the rest of theinformation. The number of “messages” involved may also vary dependingon the layer or granularity considered. For example transmitting amessage may involve using several resource elements in an LTEenvironment such that several signals at a lower layer correspond to asingle message at a higher layer. Also, transmissions from one terminalto another may relate to the transmission of any one or more of userdata, discovery information, control signalling and any other type ofinformation to be transmitted.

Also, whenever an aspect is disclosed in respect of an apparatus orsystem, the teachings are also disclosed for the corresponding method.Likewise, whenever an aspect is disclosed in respect of a method, theteachings are also disclosed for any suitable corresponding apparatus orsystem. Additionally, it is also hereby explicitly disclosed that forany teachings relating to a method or a system where it has not beenclearly specified which element or elements are configured to carry outa function or a step, any suitable element or elements that can carryout the function can be configured to carry out this function or step.For example any one or more or a mobile terminal (e.g. a D2D terminal),a relay node (e.g. a terminal-to-terminal relay node), a base station orany other mobile node may be configured accordingly if appropriate, solong as it is technically feasible and not explicitly excluded.

Whenever the expressions “greater than” or “smaller than” or equivalentare used herein, it is intended that they discloses both alternatives“and equal to” and “and not equal to” unless one alternative isexpressly excluded.

It is noteworthy that even though the present disclosure has beendiscussed in the context of LTE and/or D2D, its teachings are applicableto but not limited to LTE or to other 3GPP standards. In particular,even though the terminology used herein is generally the same or similarto that of the LTE standards, the teachings are not limited to thepresent version of LTE and could apply equally to any appropriatearrangement not based on LTE and/or compliant with any other futureversion of an LTE or 3GPP or other standard (e.g. the 5G standards).

Further particular and preferred aspects of the present invention areset out in the accompanying independent and dependent claims. It will beappreciated that features of the dependent claims may be combined withfeatures of the independent claims in combinations other than thoseexplicitly set out in the claims.

Thus, the foregoing discussion discloses and describes merely exemplaryembodiments of the present invention. As will be understood by thoseskilled in the art, the present invention may be embodied in otherspecific forms without departing from the spirit or essentialcharacteristics thereof. Accordingly, the disclosure of the presentinvention is intended to be illustrative, but not limiting of the scopeof the invention, as well as other claims. The disclosure, including anyreadily discernible variants of the teachings herein, define, in part,the scope of the foregoing claim terminology such that no inventivesubject matter is dedicated to the public.

Respective features of the present disclosure are defined by thefollowing numbered clauses:

Clause 1. A method of allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising:

allocating first resources for the first terminal to communicate via therelay node for the device-to-device communication;

allocating second resources for the second terminal to communicate viathe relay node for the device-to-device communication;

notifying the first terminal of the allocated first resources;

notifying the second terminal of the allocated second resources; and

the first and second terminals exchanging messages for thedevice-to-device communication via the relay node and using the firstand second resources, respectively.

Clause 2. A method of operating a terminal in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweenthe terminal and a further terminal, the method comprising the terminal:

receiving one or more grant messages notifying the terminal of allocatedresources for the relay node to relay the device-to-devicecommunication; and

the terminal exchanging messages with the further terminal for thedevice-to-device communication, via the relay node and using theallocated resources.

Clause 3. The method of clause 2 further comprising the terminaltransmitting a resource allocation request to the relay node for therelay node to allocate resources for relaying the device-to-devicecommunication with the further terminal.

Clause 4. A terminal for use in a mobile telecommunications system andfor using a relay node as a terminal-to-terminal relay for adevice-to-device communication between the terminal and a furtherterminal, the terminal comprising a transceiver and a controller,wherein the controller is configured to:

receive, via the transceiver, one or more grant messages notifying theterminal of allocated resources for the relay node to relay thedevice-to-device communication; and exchange, via the transceiver,messages with the further terminal for the device-to-devicecommunication, via the relay node and using the allocated resources.

Clause 5. Circuitry for a terminal for use in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweenthe terminal and a further terminal, wherein the circuitry comprises acontroller element and a transceiver element configured to operatetogether to:

receive one or more grant messages notifying the terminal of allocatedresources for the relay node to relay the device-to-devicecommunication; and

exchange messages with the further terminal for the device-to-devicecommunication, via the relay node and using the allocated resources.

Clause 6. A method of allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising:

the relay node identifying a resource pool for terminal-to-terminalrelaying; the relay node allocating first resources from the resourcepool for the first terminal to communicate via the relay node for thedevice-to-device communication;

the relay node allocating second resources from the resource pool forthe second terminal to communicate via the relay node for thedevice-to-device communication;

the relay node transmitting one or more grant messages notifying thefirst and second terminals of the allocated first and second resources;and

the first and second terminals exchanging messages for thedevice-to-device communication via the relay node and using the firstand second resources, respectively.

Clause 7. The method of clause 6 wherein the relay node identifying aresource pool comprises:

the relay node requesting a resource pool allocation from a basestation; and the base station allocating the resource pool to the relaynode.

Clause 8. The method of clause 7 wherein the relay node requesting theresource pool allocation is responsive to receiving aterminal-to-terminal relaying resource allocation request from the firstterminal.

Clause 9. The method of clause 7 or 8 further comprising the relay nodereleasing the allocated resource pool by transmitting a resource poolrelease message to the base station.

Clause 10. The method of clause 6 wherein the relay node identifying aresource pool comprises the relay node identifying a pre-allocatedresource pool.

Clause 11. The method of any of clauses 6 to 10, wherein thedevice-to-device communication is one of a unicast, a groupcast or abroadcast communication.

Clause 12. The method of any of clauses 6 to 11, wherein the relay nodeallocating first resources is at least one of: upon request from thefirst terminal; upon request from the second terminal, upon receivinginstructions from a base station and upon determination by the relaynode.

Clause 13. The method of any of clauses 6 to 12, wherein the relay nodeallocating second resources is at least one of: upon request from thefirst terminal; upon request from the second terminal, upon receivinginstructions from a base station and upon determination by the relaynode.

Clause 14. The method of any of clauses 6 to 13, wherein at least one ofthe relay node allocating first resources and the relay node allocatingsecond resources is based on one or more of:

a resource allocation request from one of the first terminal and thesecond terminal;

a determination by the relay node that it will operate as aterminal-to-terminal relay for the device-to-device communication; and

a notification from a base station and/or from one of the first andsecond terminals that the relay node has been selected for relaying thedevice-to-device communication.

Clause 15. The method of any of clauses 6 to 14, wherein the relay nodetransmitting one or more grant messages comprises at least one of:

broadcasting the first resources to a group of terminal comprising thefirst terminal; and broadcasting the second resources to a group ofterminal comprising the second terminal.

Clause 16. The method of any of clauses 6 to 15, wherein first resourcesare for one or both of: resources for the first terminal to transmitsignals to the relay node and resources for the relay node to transmitsignals to the first terminal.

Clause 17. The method of any of clauses 6 to 16, wherein secondresources are for one or both of: resources for the second terminal totransmit signals to the relay node and resources for the relay node totransmit signals to the second terminal.

Clause 18. The method of any of clauses 6 to 17, comprising the relaynode releasing the first and second sets of resources upon at least oneof:

determination that the relay node will no longer operate as aterminal-to-terminal relay for the device-to-device communication; and

termination of the device-to-device communication.

Clause 19. A method of operating a relay node for allocating resourcesin a mobile telecommunications system, the resources being for a relaynode to operate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising the relay node:

identifying a resource pool for terminal-to-terminal relaying;

allocating first resources from the resource pool for the first terminalto communicate via the relay node for the device-to-devicecommunication;

allocating second resources from the resource pool for the secondterminal to communicate via the relay node for the device-to-devicecommunication; and transmitting one or more grant messages notifying thefirst and second terminals of the allocated first and second resources.

Clause 20. The method of clause 19 further comprising the relay noderelaying, using the first and second resources, messages for thedevice-to-device communication exchanged by the first and secondterminals.

Clause 21. A relay node for allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the relaynode comprising a transceiver and a controller, the controller beingconfigured to: identify a resource pool for terminal-to-terminalrelaying;

allocate first resources from the resource pool for the first terminalto communicate via the relay node for the device-to-devicecommunication;

allocate second resources from the resource pool for the second terminalto communicate via the relay node for the device-to-devicecommunication; and

transmit, via the transceiver, one or more grant messages notifying thefirst and second terminals of the allocated first and second resources.

Clause 22. Circuitry for a relay node for allocating resources in amobile telecommunications system, the resources being for a relay nodeto operate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, whereinthe circuitry comprises a controller element and a transceiver elementconfigured to operate together to:

identify a resource pool for terminal-to-terminal relaying;

allocate first resources from the resource pool for the first terminalto communicate via the relay node for the device-to-devicecommunication;

allocate second resources from the resource pool for the second terminalto communicate via the relay node for the device-to-devicecommunication; and

transmit one or more grant messages notifying the first and secondterminals of the allocated first and second resources.

Clause 23. A method of operating a base station in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, the method comprising the basestation:

receiving, from the relay node, a resource pool allocation request;identifying a resource pool for the relay node to allocate resources forterminal-to-terminal relaying;

notifying the relay node that the identified resource pool has beenallocated to the relay node to allocate resources forterminal-to-terminal relaying.

Clause 24. A base station for use in a mobile telecommunications systemand for using a relay node as a terminal-to-terminal relay for adevice-to-device communication between a first terminal and a secondterminal, the base station comprising a transceiver and a controller,the controller being configured to:

receive, from the relay node and via the transceiver, a resource poolallocation request;

identify a resource pool for the relay node to allocate resources forterminal-to-terminal relaying;

notify, via the transceiver, the relay node that the identified resourcepool has been allocated to the relay node to allocate resources forterminal-to-terminal relaying.

Clause 25. Circuitry for a base station for use in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, wherein the circuitry comprisesa controller element and a transceiver element configured to operatetogether to:

receive, from the relay node, a resource pool allocation request;

identify a resource pool for the relay node to allocate resources forterminal-to-terminal relaying;

notify the relay node that the identified resource pool has beenallocated to the relay node to allocate resources forterminal-to-terminal relaying.

Clause 26. A method of allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising:

the relay node requesting, to a base station, resources for relaying thedevice-to-device communication;

the base station allocating first resources for the first terminal tocommunicate via the relay node for the device-to-device communication;

the base station allocating second resources for the second terminal tocommunicate via the relay node for the device-to-device communication;

the base station notifying the relay node of the allocated first andsecond resources; notifying the first terminal of the allocated firstresources;

notifying the second terminal of the allocated second resources; and thefirst and second terminals exchanging messages for the device-to-devicecommunication via the relay node and using the allocated first andsecond resources, respectively.

Clause 27. The method of clause 26 wherein at least one of the notifyingthe first terminal and notifying the second terminal is by the relaynode.

Clause 28. The method of clause 26 or 27 wherein at least one of thenotifying the first terminal and notifying the second terminal is by thebase station.

Clause 29. A method of operating a relay node for allocating resourcesin a mobile telecommunications system, the resources being for a relaynode to operate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the methodcomprising the relay node:

requesting, to a base station, resources for relaying thedevice-to-device communication; and

receiving, from the base station, a notification of allocated firstresources and allocated second resources, the allocated first resourcesbeing allocated for the first terminal to communicate via the relay nodefor the device-to-device communication and the allocated secondresources being allocated for the second terminal to communicate via therelay node for the device-to-device communication.

Clause 30. The method of clause 29 further comprising the relay nodereceiving a resource allocation request from one of the first and secondterminals for relaying the device-to-device communication.

Clause 31. The method of clause 29 or 30 wherein the relay node notifiesthe first terminal of the allocated first resources and/or notifies thesecond terminal of the allocated second resources.

Clause 32. The method of one of clauses 29 to 31 further comprising therelay node relaying, using the allocated first and second resources,messages for the device-to-device communication exchanged by the firstand second terminals.

Clause 33. A relay node for allocating resources in a mobiletelecommunications system, the resources being for a relay node tooperate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, the relaynode comprising a transceiver and a controller, the controller beingconfigured to:

request, to a base station and via the transceiver, resources forrelaying the device-to-device communication; and

receive, via the transceiver and from the base station, a notificationof allocated first resources and allocated second resources, theallocated first resources being allocated for the first terminal tocommunicate via the relay node for the device-to-device communicationand the allocated second resources being allocated for the secondterminal to communicate via the relay node for the device-to-devicecommunication.

Clause 34. Circuitry for a relay node for allocating resources in amobile telecommunications system, the resources being for a relay nodeto operate as a terminal-to-terminal relay for a device-to-devicecommunication between a first terminal and a second terminal, whereinthe circuitry comprises a controller element and a transceiver elementconfigured to operate together to:

request, to a base station, resources for relaying the device-to-devicecommunication; and

receive, from the base station, a notification of allocated firstresources and allocated second resources, the allocated first resourcesbeing allocated for the first terminal to communicate via the relay nodefor the device-to-device communication and the allocated secondresources being allocated for the second terminal to communicate via therelay node for the device-to-device communication.

Clause 35. A method of operating a base station in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, the method comprising the basestation:

receiving, from a relay node, a request for resources for relaying thedevice-to-device communication;

allocating first resources for the first terminal to communicate via therelay node for the device-to-device communication;

allocating second resources for the second terminal to communicate viathe relay node for the device-to-device communication; and

notifying the relay node of the allocated first and second resources.

Clause 36. The method of clause 35 further comprising the base station:

notifying the first terminal of the allocated first resources; and

notifying the second terminal of the allocated second resources.

Clause 37. A base station for use in a mobile telecommunications systemand for using a relay node as a terminal-to-terminal relay for adevice-to-device communication between a first terminal and a secondterminal, the base station comprising a transceiver and a controller,the controller being configured to:

receive, from a relay node and via the transceiver, a request forresources for relaying the device-to-device communication;

allocate first resources for the first terminal to communicate via therelay node for the device-to-device communication;

allocate second resources for the second terminal to communicate via therelay node for the device-to-device communication; and

notify, via the transceiver, the relay node of the allocated first andsecond resources.

Clause 38. Circuitry for a base station for use in a mobiletelecommunications system and for using a relay node as aterminal-to-terminal relay for a device-to-device communication betweena first terminal and a second terminal, wherein the circuitry comprisesa controller element and a transceiver element configured to operatetogether to:

receive, from a relay node requesting a request for resources forrelaying the device-to-device communication;

allocate first resources for the first terminal to communicate via therelay node for the device-to-device communication;

allocate second resources for the second terminal to communicate via therelay node for the device-to-device communication; and

notify the relay node of the allocated first and second resources.

Clause 39. Computer software which, when executed by a computer, causesthe computer to perform the method of any one of clauses 1, 2-3, 6-18,19-20, 23, 26-28, 29-32, 35-36.

Clause 40. A storage medium which stores computer software according toclause 39.

Clause 41. A method of allocating resources in a mobiletelecommunications system, a method of operating a terminal, a terminal,circuitry for a terminal, a method of allocating resources, a method ofoperating a relay node, a relay node for allocating resources, circuitryfor a relay node for allocating resources, a method of operating a basestation, a base station, a method of allocating resources, computersoftware and/or a storage medium substantially as hereinbefore describedwith reference to the accompanying drawings

Clause 42. Any preceding clause wherein the mobile terminal(s) and therelay node (and the base station if appropriate) are operable tocommunicate via the wireless interface using at least one of: a 3GPPcommunication protocol, an LTE communication protocol, a 4Gcommunication protocol and a 5G communication protocol.

REFERENCES

[1] Holma H. and Toskala A., “LTE for UMTS OFDMA and SC-FDMA based radioaccess”, John Wiley and Sons, 2009

The invention claimed is:
 1. A method of allocating resources in a mobile telecommunications system including a base station a relay node, the resources being for the relay node to operate as a terminal-to-terminal relay for a device-to-device (D2D) communication between a first terminal and a second terminal, the method comprising: receiving, by the relay node, a relay request from the first terminal without receiving another relay request from the second terminal; allocating, in response to receiving the relay request without receiving the another relay request and forwarding the relay request from the relay node to the base station, first resources for the first terminal to communicate via the relay node for the D2D communication with the second terminal; allocating, in response to receiving the relay request without receiving the another relay request and forwarding the relay request from the relay node to the base station, second resources for the second terminal to communicate via the relay node for the D2D communication with the first terminal; notifying, by the relay node, the first terminal of the allocated first resources; notifying, by the relay node, the second terminal of the allocated second resources; and relaying messages, via the relay node and over the first and second resources, between the first and second terminals for the D2D communication.
 2. The method of claim 1, wherein the D2D communication is one of a unicast, a groupcast or a broadcast communication.
 3. The method of claim 1, wherein the allocating the first resources is performed upon request from the first terminal, upon receiving instructions from the base station, and upon determination by the relay node.
 4. A terminal for use in a mobile telecommunications system including a base station and a relay node, the terminal using the relay node as a terminal-to-terminal relay for a device-to-device (D2D) communication between the terminal and a second terminal, the terminal comprising: a transceiver; and processing circuitry configured to control the transceiver to transmit a relay request to the relay node, wherein the second terminal does not transmit another relay request to the relay node, the relay node forwards the relay request to the base station, in response to receiving the relay request without receiving the another relay request and forwarding the relay node the relay request to the base station, first resources are allocated for the terminal to communicate via the relay node for the D2D communication with the second terminal and second resources are allocated for the second terminal to communicate via the relay node for the D2D communication with the terminal, the transceiver is configured to receive, from the relay node in response to transmitting the relay request, one or more grant messages notifying the terminal of an identification of the relay node and of the first resources allocated for the relay node to relay the D2D communication with the second terminal, and the processing circuitry is further configured to: control the transceiver to exchange messages with the second terminal via the relay node and using the first allocated resources for the D2D communication; and perform D2D communication with a third terminal without relaying messages via the relay node in a case that the a signal quality for the D2D communication between the first terminal and the third terminal is at or above the threshold.
 5. The terminal of claim 4, wherein the D2D communication is one of a unicast, a groupcast or a broadcast communication.
 6. The terminal of claim 4, wherein the allocating the first resources is performed upon request from the first terminal, upon receiving instructions from the base station, and upon determination by the relay node.
 7. The terminal of claim 4, wherein the resources allocated for the relay node include one or both of first resources for the terminal to transmit signals to the relay node, and second resources for the relay node to transmit signals to the terminal.
 8. A method of allocating resources in a mobile telecommunications system including a base station and a relay node, the resources being for the relay node to operate as a terminal-to-terminal relay for a device-to-device (D2D) communication between a first terminal and a second terminal, the method comprising: receiving, by the relay node, a relay request from the first terminal without receiving another relay request from the second terminal; identifying, by the relay node in response to receiving the relay request without receiving the another relay request, a resource pool for terminal-to-terminal relaying; allocating, in response to receiving the relay request without receiving the another relay request and forwarding the relay request from the relay node to the base station, first resources from the resource pool for the first terminal to communicate via the relay node for the D2D communication with the second terminal; allocating, in response to receiving the relay request without receiving the another relay request and forwarding the relay request from the relay node to the base station, second resources from the resource pool for the second terminal to communicate via the relay node for the D2D communication with the first terminal; transmitting, by the relay node, one or more grant messages notifying the first and second terminals of the allocated first and second resources; and relaying messages, via the relay node and over the first and second resources, between the first and second terminals for the D2D communication.
 9. The method of claim 8, wherein the relay node identifying a resource pool comprises: requesting a resource pool allocation from the base station; and receiving an allocation of the resource pool from the base station.
 10. The method of claim 9; wherein the requesting the resource pool allocation is responsive to receiving the relay request from the first terminal.
 11. The method of claim 9, further comprising: releasing the allocated resource pool by transmitting a resource pool release message to the base station.
 12. The method of claim 8, wherein the identifying a resource pool comprises the relay node identifying a pre-allocated resource pool.
 13. The method of claim 8, wherein the D2D communication is one of a unicast, a groupcast or a broadcast communication.
 14. The method of claim 8, wherein the relay node allocating first resources is at least one of: upon request from the first terminal; upon request from the second terminal; upon receiving instructions from the base station; and upon determination by the relay node.
 15. The method of claim 8, wherein the relay node allocating second resources is at least one of: upon request from the first terminal; upon request from the second terminal; upon receiving instructions from the base station; and upon determination by the relay node.
 16. The method of claim 8, wherein at least one of the allocating first resources and the allocating second resources is based on one or more of: a resource allocation request from one of the first terminal and the second terminal; a determination by the relay node that it will operate as a terminal-to-terminal relay for the D2D communication; and a notification from the base station and/or from one of the first and second terminals that the relay node has been selected for relaying the D2D communication.
 17. The method of claim 8, wherein the transmitting one or more grant messages comprises at least one of: broadcasting the first resources to a group of terminal comprising the first terminal; and broadcasting the second resources to a group of terminal comprising the second terminal.
 18. The method of claim 8, wherein the first resources are for one or both of resources for the first terminal to transmit signals to the relay node and resources for the relay node to transmit signals to the first terminal.
 19. The method of claim 8, wherein the second resources are for one or both of resources for the second terminal to transmit signals to the relay node and resources for the relay node to transmit signals to the second terminal.
 20. The method of claim 8, further comprising releasing the first and second sets of resources upon at least one of: determination that the relay node will no longer operate as a terminal-to-terminal relay for the D2D communication; and termination of the D2D communication. 